Patent GB-183256-A (GB)
Title: Sewing machine
IPC: D05B3/06
Filed: 1921-04-21
Abstract: 183,256. Fairweather, W., (Singer Manufacturing Co.). April 21, 1921. Button-hole sewing-machines; feed by co-operating jaws; needles vibrating laterally.-Mechanism for varying to either a predetermined or an arbitrary degree the workspacing movements of the button hole-cutting, and workspacing device described in Specification 185,711 and also applicable to the varying of the movements of laterally jogging needles or in the feeding or ruffling mechanisms for special classes of work comprises amanually actuated element which is arrested by a stop at a predetermined position under a normal impulse, but may be moved further to an arbitrary extent under an abnormal impulse owing to the elasticity of the stop. In the machine shown, a buttonhole cutting and work-shifting arm 27 is pivoted at 40 to a frame connected by a link member to a swinging bracket having a hub 50. A guide-rod 43 of the frame carries a sleeve 51 which may be clamped thereon by a screw 52 and is pivotally connected to a sleeve 56 which may be clamped by a screw 61 on an inclined fixed guide-rod 57. The arrangement allows the radius of movement of the cutter-arm to be varied. A ball-stud on the arm 27 is connected by a link 64 to a projection 66 on a rock-arm 67, Fig. 5, the link 68 of which is loosely mounted on a rock shaft 69, Figs. 1 and 4. An arm 72 fixed on the shaft 69 carries a stud 73 engaging an arm 75 of a lever 76 fulcrumed at 77 and carrying a tappet member 81 which lies in the path of roller-stud 82 projecting from the main cam 15. An arm 85 is mounted on the shaft 69 adjacent to the arm 67 and is locked to the arm by a latch-lever 89 pivoted in lugs 86 and pressed by a spring 91 so that its nose 93 engages a recess 94. A lateral lug 96 on the arm 67 ensures the correct alignment therewith of the arm 85. An arm 99 loosely mounted on the hub 68 of the arm 67 has a series of holes 100 arranged at an angle with a similar series 101 in the arm 67, and adapted to receive a locking pin 102 having an eccentric locking flange 103<1>, Fig. 7. A lateral lug 104 on the arm 99 carries a contact screw 105 which is normally held, by the action of a spring 108 controlling the rock-shaft, in contact with a stop plate 109 on an arm 110 pivotally mounted in the frame and acted on by a spring 115, Fig. 4, to keep the edge of the plate normally in contact with a recess 1" in the frame. An operating-lever 121 mounted loosely on the fulcrum of the arm 110 is provided with an arm 120 having a slot 119 inclined to a radial line and along which is slidable a locking stud 118 having engagement with a radial slot in the arm 110 thus providing for relative adjustment of the arms 120 and 110. An arm 122 of the lever carries a stud 128 the range of movement of which is normally limited by the end of a spring 129 which rests normally on a stud 131 and is adjustable by a screw 132, Fig. 1. The depression of the arm 27 into nipping contact with the work is effected at the moment when the presser arms are lifted by the engagement of an adjustable cam rib 150 on the cam 15 with a stud 149 which, through a spring- controlled slide, causes the yielding pressure of a bar 136 upon a stud 135 on the arm 27. After the shift of the work has taken place the forcible depression of the arm to cut a button hole is effected by the engagement with the stud 135 of a plunger 153 reciprocated by a cam 159 geared to the cam 15. A hand-actuated starting-lever 8, Fig. 4, is connected by a link 164 to an arm 166 mounted on a rock-shaft 168 which has an oppositely extending arm 169 pivotally connected to a push rod 172. A notch 173 in the rod 172 rests on a pin 174 of a trip lever having an arm 177 with a bevelled lower' edge resting on the inclined edge 93 of the latch 89. If it is desired to prevent the work-shifting movement of the cutting and work-shifting device the lever 8 is given a movement opposite to the normal starting movement which causes the arm 172 to depress the arm 177 and move the latch 89 so as to uncouple the driving-arm 85 from the driver arm 67. In the normal working of the machine when the distances between the button holes of a series are constant the retracted position of the projection 66 on the operating arm 67, which determines the throw of the work-shifting and cutting arm and hence the distance between successive button-holes, is fixed by the relative setting of the arms 67, 99 and the machine works automatically. When however it is desired to vary the spacing at any moment to a predetermined extent the stud 118 is set at the required graduation of a scale 125 and the lever 121 rocked to bring the stud 128 into contact with the spring 129 the consequent displacement of the stop plate 109 altering the retracted position of the arms 99 and 67. An arbitrary variation at the will of the operator is obtained by additional pressure on the lever 121 sufficient to cause deformation of the spring 129 by the stud 128 and hence a further movement of the plate 109. In a modification, Fig. 9, the plate 109<1> rests on a spring 178 and hence is susceptible of motion in both senses under suitable actuation bv the lever 121 so that the spacing can be both increased or decreased from the normal.